Fire extinguishing means



nited tates act 3,074,883 Patentedv Jan. 22, 1963 3,074,883 FIRE EXTINGUISHING MEANS Henry A. Letteron, Schenectady, N.Y., assignor to General Electric Company, a corporation of New York No Drawing. Filed June 28, 1961, Ser. No. 120,173 3 Claims. (Cl. 252-2) This invention relates to fire extinguishing means. More particularly, it relates to fire extinguishing means which has the capability of completely enveloping burning materials.

The use of fire extinguishing media which are intended to envelop burning material excluding therefrom the access of air and thus extinguishing its burning is well known. For example, it is well known to use foams of various types for extinguishing fires. Likewise, the use of powdered materials for such purpose is also extensive. However, the known compositions for fire extinguishing purposes are beset by various disadvantages. For example, foaming materials, unless used in large quantities, are incapable of completely and efficiently enveloping burning material so as to exclude air or oxygen therefrom. Such foams also require extensive clean-up operations where equipment and the like so covered are to be salvaged and reused. The same is true of powdered materials. Powdered fire extinguishing materials further do not adhere adequately to the burning material and are easily blown away in air currents or disrupted. Also, such powdered materials are often used as a stop-gap measure to preliminarily quench flaming until other extinguishing material such as water can be brought into play to lower the temperature of the combustibles, to quench them thoroughly and to prevent resurgence of flame from charred or glowing hot material.

It is a principal object of this invention to provide an improved fire extinguishing material which has the capability of completely quenching and enveloping burning material to the exclusion of ambient air or oxygen while using a relatively small amount of such extinguishing medium.

Briefly, the invention relates to fire extinguishing material and means for extinguishing fires comprising a slurry of finely divided surface-active mica material in an incombustible medium, such as water.

Those features of the invention which are believed to be patentable are set forth with particularity in the claims appended hereto. The invention will, however, be better appreciated and further objects and advantages thereof become apparent from a consideration of the following description.

The finely divided micaceous material used in conjunction with the invention is well known. Any of the naturally occurring or synthetic mica or micaceous materials characterized by a flat or plate-like crystal structure can be used. The term mica is used herein as applying to all such materials. The micaceous material is finely divided by any of the known processes for producing surface-active materials. A convenient process is that described in Bardet Patent 2,549,880 and related patents, among others. According to this process, mica is dehydrated at elevated temperatures of the order of about 800 C. after which the treated flakes are placed in a liquid medium where they are broken up to form a pulp.

Another process for producing the present finely divided micaceous material is that disclosed in copending application Serial No. 810,566, filed May 4, 1959, assigned to the same assignee as this invention and included herein by reference. There is described in this application the process of delaminating micaceous and similar material by coating the material with an adhesive and applying a peeling force which is greater than the bonding force between the physical elements of the material. This process, when applied repetitively, reduces the material to a very fine state. Upon removal of the adhesive, fine platelets are produced which can be formed into a slurry with water for the present purpose. This process does not depend upon dehydration of the mica and can, therefore, be applied to any micaceous or plate-like material to provide platelets having tightly clingable surfaces in the dry or partially dry state.

The present micaceous materials are characterized by the fact that the tiny flakes or platelets so produced are surface-active or have active or virgin surfaces which, when the platelets are laid down in a layer from a water or other compatible liquid slurry, are tightly interlocked.

In extinguishing fire, the slurry or finely divided surface-active mica in water or other suitable non-combustible compatible material can be applied directly to the burning material in any usual manner. That is, it may be pumped on the fire through ordinary fire-fighting hoses or from fire extinguishers or even thrown on the burning material.

When the mica slurry contacts the burning material, the water or other liquid serves, of course, to lower the temperature of the burning material and thus extinguishes the flame. At the same time, the tiny mica flakes in the slurry coat the burning material with a continuous sheath of tiny interlocked platelets which adhere thereto and to each other to effectively exclude oxygen or air and thus prevent reignition of the material.

It will be seen that the present material accomplishes its purpose of fire extinguishing in a one-step process, as compared, for example, to powder extinguishers whose use must usually be followed up with water. The mica is easily brushed from the coated article when desired.

The concentration of mica in the slurry depends in large part on the equipment which is used to lay the slurry on the fire. agitating pump can be used for such purpose more concentrateld slurries may be used ranging up to about 10 percent, by weight, of mica. Where hand equipment is used, lower concentrations of mica ranging from about 1 to 7 percent, by weight, are preferred, such concentrations being kept in suspension often by merely shaking the fire extinguisher or container. In many cases, the pumping action of a hand operated fire extinguisher is suflicient to keep the mica in suspension so that higher concentrations of mica can be used.

It will be realized that the mica slurry can also be simply thrown on the fire from an open container. Likewise, these micaceous slurn'es are very adaptable to being stored in a sealed, flexible bag or envelope of thermoplastic film. When fire occurs the bag can simply be thrown at the fire whereupon the bag melts or bursts spreading the slurry over the fire. If desired, the bag may be kneaded to more thoroughly mix the slurry when indicated. Such containers are particularly suitable for home Particularly where means such as an use or in automobiles where they can be easily stored until required.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The process of extinguishing fire which comprises applying to said fire a water slurry of from about 1 to 10 percent by weight of finely divided surface-active mica contained in a sealed bag of thermoplastic film.

2. The process of extinguishing fire which comprises applying to said fire a Water slurry of finely divided surface-active mica, said slurry containing from about 1 to 10 percent by weight of said mica.

3. The process of extinguishing fire which comprises applying to said fire a water slurry of from about 1 to 7 percent by weight of finely divided surface-active mica.

References Cited in the file of this patent UNITED STATES PATENTS 

1. THE PROCESS OF EXTINGUISHING FIRE WHICH COMPRISES APPLYING TO SAID FIRE A WATER SLURRY FROM ABOUT 1 TO 10 PERCENT BY WEIGHT OF FINELY DIVIDED "SURFACE-ACTIVE" MICA CONTAINED IN A SEALED BAG OF TERMOPLASTIC FILM. 